Disposable battery powered screw driver, locking mechanism, and accessories

ABSTRACT

In accordance with one embodiment of the present invention, a driver may include an electric motor coupled to a bit interface. The bit interface may include a generally cylindrical body having first and second hollow portions. The first hollow portion may be on one end of the generally cylindrical body and may define a generally cylindrical hole. The second hollow portion may abut the first hollow portion and define an oblong channel. The oblong channel may be further defined by first and second parallel flat walls. The cylindrical body may also include a first transverse groove.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to disposable surgical tools andmore particularly to a disposable battery powered screw driver, lockingmechanism and accessories.

BACKGROUND OF THE INVENTION

Many different tools are used during surgical procedures to facilitatedifferent aspects of the procedures. A commonality to all surgical toolsis that they should be sterilized prior to use during a surgicalprocedure to minimize the chance of patient infection. The health careindustry expends a considerable amount of time and money to performthese sterilizations. In the case of many surgical tools, the tools areshipped sterile from the manufacturer. If these tools are designed to bereusable, the tools will require resterilization following use. Theseresterilizations can be performed by the hospital, or the tools may bereturned to the manufacturer for resterilization. In either case, anadditional expense is incurred by the need to maintain sterilizationequipment and personnel trained in its use, or by additional shippingand transaction costs.

Sterilization concerns are magnified for battery powered power tools asthere are additional concerns about battery life and/or recharging thebattery. Starting a procedure with a partially charged tool runs therisk that the tool battery may not last for the entire procedure.Therefore, a sterile charging environment may be required, or the toolsmay need to be recharged prior to sterilization. This increases thetool's down time and requires that a hospital keep extra tools on hand.The extra tools must also be maintained and kept sterile, once againincreasing costs

SUMMARY OF THE INVENTION

In accordance with the teachings of the present invention, thedisadvantages and problems associated with surgical power tools havebeen substantially reduced or eliminated. In particular, the system andmethod described herein provide for single use drivers that reduce oreliminate the need for resterilization procedures and may be relied uponto last through a procedure.

In accordance with one embodiment of the present invention, a driver mayinclude an electric motor coupled to a bit interface. The bit interfacemay include a generally cylindrical body having first and second hollowportions. The first hollow portion may be on one end of the generallycylindrical body and may define a generally cylindrical hole. The secondhollow portion may abut the first hollow portion and define an oblongchannel. The oblong channel may be further defined by first and secondparallel flat walls. The cylindrical body may also include a firsttransverse groove.

The driver may also include a retaining clip seated in the firsttransverse groove and operable to secure a driver bit in the bitinterface. The electric motor and the bit interface may be at leastpartially surrounded by a plastic housing. The driver may also include abattery operable to power the electric motor, and a flex circuitoperable to electrically couple the electric motor to the battery. Thedriver may also utilize a gear reduction process to translate theangular velocity generated by the electric motor into torque. At leastone plastic gear may be used.

In accordance with another embodiment of the present invention, a drivermay include a bit interface coupled to a driver bit, and a retainingclip coupled to both the bit interface and the driver bit. The bitinterface may include a generally cylindrical body having first andsecond hollow portions. The first hollow portion may be on one end ofthe generally cylindrical body and define a generally cylindrical hole.The second hollow portion may abut the first hollow portion and definean oblong channel. The oblong channel may be further defined by firstand second parallel flat walls. The cylindrical body also includes atransverse groove. The driver bit may include a cylindrical shaft with ascrew head interface on one end and an anti-rotation interface on theother end. The anti-rotation interface may include first and secondparallel flats. The cylindrical shaft may also include a retentiongroove. The first and second flats may be disposed between the first andsecond flat walls and a portion of the cylindrical shaft proximate thefirst and second flats may be disposed within the first hollow portion.The transverse groove may align with the retention groove and theretaining clip may be at least partially disposed within the transversegroove and the retention groove.

Technical advantages of certain embodiments of the present inventioninclude a surgical driver which is inexpensive to replace and designedto be disposed of after use. This eliminates the need for the hospitalto resterilize the driver for another procedure. The driver ismanufactured from inexpensive parts, and is therefore inexpensive toreplace after each procedure. Therefore, it is cost effective forhospitals to dispose of the driver following its use, rather thanattempting to resterilize and reuse the driver.

Another technical advantage of certain embodiments of the presentinvention is a disposable surgical driver containing a battery withsufficient power to last for at least the duration of one surgicalprocedure. This eliminates concerns of a battery having insufficientcharge during a procedure to complete the procedure.

A further technical advantage of certain embodiments of the presentinvention is a driver utilizing a gear reduction mechanism. By usinggear reduction, the power requirements of the driver motor may bereduced. This allows for a smaller and lower voltage battery to be used.The battery life, and thereby the tool life, may also be extended.

Other technical advantages of the present invention will be readilyapparent to one skilled in the art from the following figures,descriptions, and claims. Moreover, while specific advantages have beenenumerated above, various embodiments may include all, some, or none ofthe enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates one embodiment of a disposable driver in accordancewith the present invention;

FIGS. 2A and 2B illustrate the driver of FIG. 1 with a portion of thehousing removed; and

FIG. 3 illustrates the bit retention system and driver bit of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a disposable driver 30 for use in surgicalprocedures. Driver 30 is designed to be inexpensive to manufacture, andtherefore inexpensive to replace for each surgical procedure.

Disposable surgical tools are desirable because tools used in surgerymust be sterilized. Many tools used in surgical procedures aresterilized prior to shipping from the manufacturer and are packaged tomaintain the tool's sterility. If surgical tools are to be reused, thenhospitals must invest in equipment and employee time to perform thesterilizations. Further, sterilization techniques may involve hightemperatures or harsh chemicals, and tools intended to be resterilizedwould need to be capable of withstanding the sterilization conditionswhile maintaining their functionality.

In the specific instance of power tools, rechargeable batteries degradeover the life of the tools. As a tool gets older, the battery lasts fora continuously decreasing time period. Sterilization procedures may alsoreduce battery life. In addition, these tools typically require theintervention of a person to recharge them. The combination of humanerror in forgetting to charge the battery of a tool, with mechanicalerror caused by an aging battery, may result in failure of a tool duringa surgical procedure. Stopping a surgical procedure to secure anothertool is not desirable. Neither is maintaining backup tools in the eventof tool failure. For at least these reasons, it is desirable to haveinexpensive surgical tools which do not require resterilization orrecharging following a surgical procedure, and have sufficient power tolast for an entire procedure. Driver 30 is designed to meet theserequirements.

In one embodiment, the driver housing may be made of a commercial gradeplastic, such as polycarbonate/polyester. This plastic is cost effectivefor a single use device, but does not hold up well to the hightemperature and high moisture that is associated with repeatedautoclaving (sterilization). A plastic may be used to manufacture thegears and bearings, such as straight and glass filled nylon. Theseplastics also do not hold up well to the moisture, without swelling,associated with repeated autoclaving. Devices designed to surviverepeated autoclaving might need to be made from more costly materialssuch as aluminum, stainless steel, or high temperature, low moistureabsorbing plastics such as Radel, Ultem or other more expensiveplastics.

The driver battery may be a low cost non-rechargeable lithium typebattery that loses at least half of its energy when autoclaved one time.The driver motor may be an inexpensive DC motor like those found inretail battery powered devices like electric shavers, poweredscrewdrivers or motor driven toys. The driver motor is not designed tosurvive autoclaving because it is constructed out of carbon steels thatmay rust, and plastics that cannot hold up to the high temperature andmoisture that are common with autoclaving.

Reusable tools present the problem of cleaning tool crevices, and thesterility of autoclaved power tools may be questionable. Reusable powertools may also break down from repeated use and repeated autoclaving. Ifa tool breaks down in the middle of a procedure, a replacement has to befound and sterilized to finish the procedure. Issues also arise frombattery powered devices which include autoclavable batteries that looseenergy when autoclaved. Hospital billing may also be simplified by usinga single use device as a single patient may be billed for the toolrather than attempting to capitalize the cost of a reusable tool overthe number of procedures in which it is expected to be used.

In the illustrated embodiment, driver 30 includes a two-piece housing32. The two halves of housing 32 may be snapped together, held togetherby screws, held together by epoxy, or held together by anotherappropriate mechanism. In an alternative embodiment, housing 32 couldinclude more than two pieces held together in any appropriate manner.

Coupled to the front of driver 30 is bit 34. In the illustratedembodiment, bit 34 includes a rotational interface 35 that is configuredto interface with a Phillips head screw. Alternative embodiments of bit34 may include a rotational interface 35 configured to interface withtaps, drill bits, adaptors, or other screw types such as flat head,Allen, Torx, square, or other screw head configurations. Alternatively,rotational interface 35 may not be configured to interface with a screwhead, but may be configured to interface with a nut, such as a hex nut,or may be configured to receive a driver bit, or drill a hole throughmaterial such as bone.

Bit 34 may be rotated by pressing forward button 36 or reverse button38. Driver 30 is configured such that pressing reverse button 38 causesbit 34 to rotate in the opposite direction as it would if forward button36 were pressed. By pressing forward button 38 a screw may be installedor a hole may be drilled. By pressing reverse button 38 a screw may beremoved or a bit may be withdrawn. Forward button 36 and reverse button38 may be made from a flexible material such as rubber, or they may bemade from a rigid material such as a hard plastic.

In the illustrated embodiment, driver 30 includes ridges 40 on housing32. These ridges may be incorporated to improve the gripping surface ofdriver 30 and to prevent slippage or loss of grip on driver 30.Alternative embodiments could improve the grip on driver 30 in manydifferent ways, for example, by including knurling, heavy texturing, orproviding protrusions to prevent slipping.

FIGS. 2A and 2B illustrate driver 30 with one half of housing 32removed. Forward button 36 and reverse button 38 are shown electricallycoupled to battery 42 and motor 44. In the illustrated embodiment, theelectrical coupling is provided by circuit board 46. circuit board 46may be a nonconductive material that has an electrical circuit disposedon or within it. In alternative embodiments, the electrical coupling ofthe components of driver 30 could be accomplished using a flex circuitwith an electrical circuit disposed on or within it, or by traditionalwires. In one embodiment, a flex circuit may be used which is made of aflooded single sided 2 oz copper etch on a polyimide substrate. Thesingle sided circuit is inexpensive, and the flooded 2 oz copper etchprovides adequate current carrying ability and low voltage drop.Alternative embodiments of driver 30 may use multi-layer flex circuits,silver ink etch, or substrates such as polyesters. Further alternativeembodiments may utilize metal strips or discrete wires.

Battery 42 could be any type of battery capable of supplying motor 44with its required voltage and current. In one embodiment, motor 44 mayoperate on 3 volts DC. In alternative embodiments, motor 44 may operateon any desired voltage and current. Battery 42 would have acorresponding voltage range and be capable of providing this voltage forat least the entire designed life of driver 30 (e.g., for the durationof one surgical procedure).

In the illustrated embodiment, motor 44 does not need to be a highpowered motor or even be capable of providing sufficient torque toinstall a screw or drive a driver bit. This is true because motor 44does not directly drive bit 34, but transmits the drive forces through aset of transmission gears 48. Transmission gears 48 utilize agear-reduction technique to translate angular velocity into torque.

Motor 44 is coupled to and turns drive gear 50. Drive gear 50 then turnsthe first transmission gear 48. Transmission gears 48 include a largegear 52 and a small gear 54. Large gear 52 and small gear 54 are coupledsuch that they turn as one unit. Drive gear 50 turns the first largegear 52. This also causes the first small gear 54 to turn at the samerate as the first large gear 52. First small gear 54 interfaces with andturns the second large gear 52. In this manner, the second large gear 52is turning more slowly, i.e. has less angular velocity, than the firstlarge gear 52, but the second large gear 52 is turning with more torquethan the first large gear 52. This gear-reduction technique may be usedas many times as is desired to translate the angular velocity of drivegear 50 into the desired torque at bit 34. In the illustratedembodiment, three stages of gear reduction are utilized, as evidenced bythe three transmission gears 48. In alternative embodiments, any numberof gear reduction steps could be utilized, or motor 44 could directlydrive bit 34.

The small gear 54 of the final transmission gear 48 is coupled to andturns interface gear 56. Interface gear 56 is coupled to bit interface58 in such a manner that bit interface 58 turns when interface gear 56is turned. Bit 34 is also securely fixed to bit interface 58 such thatbit 34 turns when bit interface 58 is turned. In this manner, motor 44is capable of driving bit 34. Each side of the transmission gears 48 andone side of interface gear 56 are supported by bearings 60. Though someof these components share bearings 60, the components are not connectedthrough the bearings 60 and are therefore free to spin at differentangular velocities.

Transmission gears 48 may be cut or cast from a single material as onepiece units, or large gears 52 may be separate pieces of the same ordifferent material as small gears 54. In a like manner, interface gear56 and bit interface 58 may be cut or cast from a single material as onepiece units, or interface gear 56 may be a separate piece of the same ordifferent material as bit interface 58.

FIG. 3 is an enlarged view illustrating bit 34 decoupled from bitinterface 58. Bit interface 58 and bit 34 are designed to havecorresponding features such that they fit together and may be securelycoupled. Further, retaining clip 62 is coupled to both bit interface 58and bit 34 and serves to further secure the two pieces together.

Bit interface 58 has a generally cylindrical shape, however, portions ofbit interface 58 have been hollowed to accept bit 34. A first portion 64of bit interface 58 has had its center portion removed such that ahollow cylinder or tube remains. The hole created in first portion 64 bythe removal of it center portion is sized to be slightly larger thanshank 72 of bit 34. This allows shank 72 of bit 34 to be inserted intothe end of bit interface 58.

Abutting first portion 64, a second portion 66 has had an oblong sectionremoved such that an oblong hole passes from one side of bit interface58 to the other. The removal of the oblong section of second portion 66leaves two parallel flat walls 68. Flat walls 68 interface with flats 70on bit 34 and the combination keeps bit 34 from rotating independentlyfrom bit interface 58.

Second portion 66 may abut or overlap first portion 64 such that theoblong hole cut from second portion 66 intersects the hole in firstportion 64. This allows bit 34 to be inserted into bit interface 58 suchthat flats 70 interface with flat walls 68 and the portion of shank 72immediately beyond flats 70 interfaces with the hole in first portion64. The remainder of bit 34 protrudes from the front of bit interface 58and driver 30.

Retaining clip 62 keeps bit 34 from falling out of bit interface 58.Retaining clip 62 is seated in grooves 74 cut into bit interface 58. Asbit 34 is inserted into bit interface 58, the arms of retaining clip 62are forced apart by rounded end 76 on bit 34. Bit 34 is pushed into bitinterface 58 until the arms of retaining clip 62 close over grooves 78on bit 34. When installed in this manner, retaining clip 62 is seated ingrooves 74 on bit interface 58 and grooves 78 on bit 34 and holds bit 34securely within bit interface 58.

Retaining clip 62 is illustrated as having two relatively straight armsjoined by an arcuate section. One of the arms includes a bent sectionwhich faces the other arm and prevents retaining clip 62 from slippingoff of bit interface 58. In the illustrated embodiment, each of the armsof retaining clip 62 are seated in a groove 74 and a groove 78.Alternative embodiments may use retaining clips of many different shapessuch as a clip with an arcuate arm and a straight arm. In some suchembodiments, only one of the arms may be seated in a groove on the bitinterface and a groove on the bit. Other alternative embodiments couldinclude a bent section on each arm to prevent the retaining clip fromslipping off of the bit interface. In further alternative embodiments,any shape of retaining clip 62 capable of securing bit 34 in bitretainer 58 may be used.

The force required to insert or remove bit 34 from bit interface 58 maybe adjusted by changing the design of retaining clip 62. For instance,in the illustrated embodiment, retaining clip 62 is formed from a roundpiece of metal stock. The strength of retaining clip 62, and thereforethe force required to separate the arms of retaining clip 62, could beincreased by increasing the diameter of the metal stock used to formretaining clip 62. In alternative embodiments, retaining clip 62 couldbe formed from metal with cross sections that are not round, or may beformed from round or non-round non-metals.

In the illustrated embodiment, grooves 74 are located in second portion66 and grooves 78 are placed correspondingly. In alternativeembodiments, grooves 74 and 78 may be placed at nearly any point alongfirst portion 64 or second portion 66 to change the position ofretaining clip 62.

During a surgical procedure, it may be desirable to change bit 34 fromone type of bit to another. For instance, a surgeon may wish to changefrom a drilling bit to a bit with a Phillips head screw driver. In theillustrated embodiment, bit 34 contains a ridge 80 which may be used tofacilitate removing bit 34 from bit interface 58. Ridge 80 provides anincreased diameter surface which can be pulled on to remove bit 34.Alternative embodiments may place ridge 80 in a different spot on shank72, may use alternative grip enhancing features, or may not include anygrip enhancing features. In an alternative embodiment, ridge 80 or thetrough formed on either side of ridge 80 may be painted, or otherwisecolor coded with a color or symbol indicating the type or size of bit34. In this embodiment, bits may be easily interchanged without needingto examine the end of the drill bit or look for small etchings on theside of the bit to ensure the bit is the desired bit.

Although the present invention has been described in severalembodiments, a myriad of changes and modifications may be suggested toone skilled in the art, and it is intended that the present inventionencompass such changes and modifications as fall within the scope of thepresent appended claims.

1. A driver, comprising: an electric motor; and a bit interface coupledto the electric motor, the bit interface including: a generallycylindrical body defining a longitudinal bore extending from a first endof the cylindrical body to a central portion of the cylindrical body;wherein the central portion of the cylindrical body defines an oblongchannel that extends radially through the cylindrical body and thelongitudinal bore; wherein the oblong channel is further defined by: afirst flat wall; and a second flat wall generally parallel to the firstflat wall; and the central portion of the cylindrical body furtherdefining a first transverse groove adjacent the oblong channel andextending generally perpendicular to the longitudinal bore.
 2. Thedriver of claim 1, further comprising a retaining clip operable tosecure a driver bit in the bit interface and wherein the retaining clipis coupled to the generally cylindrical body and seated in the firsttransverse groove.
 3. The driver of claim 2, wherein the force requiredto remove the driver bit from the bit interface is determined by thediameter of the retaining clip.
 4. The driver of claim 2, furthercomprising: the central portion of the cylindrical body further defininga second transverse groove adjacent the oblong channel and extendinggenerally perpendicular to the longitudinal bore; the second transversegroove being generally parallel to the first transverse groove; and theretaining clip being seated in the second transverse groove.
 5. Thedriver of claim 1, further comprising a plastic housing at leastpartially enclosing the electric motor and the bit interface.
 6. Thedriver of claim 1, further comprising a battery operable to power theelectric motor.
 7. The driver of claim 6, further comprising a flexcircuit operable to electrically couple the electric motor to thebattery.
 8. The driver of claim 1, wherein the electric motor isoperable to turn the bit interface in a direction selected from thegroup consisting of clockwise and counter-clockwise.
 9. The driver ofclaim 8, wherein the direction that the bit interface is turned isselected by depressing a forward button or a reverse button.
 10. Thedriver of claim 1, further comprising a plurality of dissimilarly sizedgears, and wherein the angular velocity generated by the electric motoris translated into torque by a gear-reduction process.
 11. The driver ofclaim 1, further comprising the electric motor being coupled to the bitinterface by a plurality of gears.
 12. The driver of claim 11, whereinat least one of the plurality of gears comprises a plastic gear.
 13. Adriver bit retainer, comprising: a generally cylindrical body defining alongitudinal bore extending from a first end of the cylindrical body toa central portion of the cylindrical body; wherein the central portionof the cylindrical body defines an oblong channel that extends radiallythrough the cylindrical body and the longitudinal bore; wherein theoblong channel is further defined by: a first flat wall; and a secondflat wall generally parallel to the first flat wall; and the centralportion of the cylindrical body further defining a first transversegroove adjacent the oblong channel and extending generally perpendicularto the longitudinal bore.
 14. The driver bit retainer of claim 13,further comprising: the central portion of the cylindrical body furtherdefining a second transverse groove adjacent the oblong channel andextending generally perpendicular to the longitudinal bore; and thesecond transverse groove being generally parallel to the firsttransverse groove.
 15. The driver bit retainer of claim 14, wherein thefirst transverse groove and the second transverse groove areperpendicular to a longitudinal axis of the generally cylindrical body.16. The driver bit retainer of claim 14, wherein the first transversegroove and the second transverse groove intersect the oblong channel.17. A driver, comprising: an electric motor; a battery electricallycoupled to the electric motor; a bit interface coupled to the electricmotor by a plurality of transmission gears; wherein the plurality oftransmission gears are operable to translate the angular velocitygenerated by the electric motor into torque; wherein the bit interfaceincludes: a generally cylindrical body defining a longitudinal boreextending from a first end of the cylindrical body to a central portionof the cylindrical body; an interface gear coupled to a first end of thegenerally cylindrical body, the interface gear operable to interfacewith at least one of the plurality of transmission gears; wherein thecentral portion of the cylindrical body defines an oblong channel thatextends radially through the cylindrical body and the longitudinal bore;wherein the oblong channel is further defined by: a first flat wall; anda second flat wall generally parallel to the first flat wall; thecentral portion of the cylindrical body further defining first andsecond transverse grooves adjacent the oblong channel and extendinggenerally perpendicular to the longitudinal bore; wherein the firsttransverse groove is generally parallel to the second transverse groove;wherein the first and second transverse grooves are on opposite sides ofthe generally cylindrical body; and wherein the first and secondtransverse grooves each intersect the oblong channel; a retaining clipcoupled to the generally cylindrical body and operable to secure adriver bit in the bit interface; wherein the retaining clip is seated inthe first and second transverse grooves; and a plastic housing at leastpartially enclosing the electric motor, the battery, the bit interface,and the plurality of transmission gears.
 18. A method, comprising:coupling an electric motor to a bit interface such that the bitinterface turns when the electric motor is activated; wherein the bitinterface includes: a generally cylindrical body defining a longitudinalbore extending from a first end of the cylindrical body to a centralportion of the cylindrical body; wherein the central portion of thecylindrical body defines an oblong channel that extends radially throughthe cylindrical body and the longitudinal bore; wherein the oblongchannel is further defined by: a first flat wall; and a second flat wallgenerally parallel to the first flat wall; and the central portion ofthe cylindrical body further defining a transverse groove adjacent theoblong channel and extending generally perpendicular to the longitudinalbore.
 19. The method of claim 18, further comprising: sterilizing thebit interface and electric motor; sealing a package that encloses thebit interface and electric motor after sterilizing the bit interface andelectric motor; shipping the bit interface and electric motor aftersealing the package.
 20. The method of claim 18, further comprisingcoupling a bit to the bit interface by inserting a back end of the bitinto the bit interface until a retaining clip seated in the transversegroove engages a retention groove on the bit.